[apparmor] [Patch 0/4] change accept node handling during expr tree set

[John Johansen]

On 06/22/2015 10:59 AM, John Johansen wrote:
> This series of patches changes the way accept nodes are generated
> and the expression tree is set-up around them. It is a start to the
> backend refactoring and cleanup, and provides a nice little performance
> boost in most cases because
>   1. It reduces the number of accept nodes geneted and considered during
>      simplification/factoring, and node set building (shorter node sets
>      to construct and compare)
>   2. It reduces the number of Alt nodes (used to combine the accept nodes)
>      to consider during simplfication, and node set building (agin shorter
>      node sets to construct and compare)
>   3. It reduces the number of nodes that must be consider in any given
>      simplification pass, by separating out node sets that can't be
>      simplified on the right hand simplification/factoring pass.
> 
> The performance change is dependent on the profile being parsed, and
> there is no guarentee that it will be faster for all profiles. With that
> being said, I haven't seen any performance regressions+ and some fairly
> nice performance improvements so its worth considering before the rest
> of the backend factoring is done.
> 
> Eg. Using a few example profile tests from a local machine, comparing
> against the 2.9 parser in Ubuntu 14.10 against current 2.10 with
> these patches*
> 
> profile       with tree simplification      -O no-expr-simplify
> -------       -----------------------       -------------------
> evince              22% faster                   10% faster
> firefox             40% faster                   11% faster
> chromium            32% faster                   11% faster
> cupsd               35% faster                    3% faster
> dnsmasq             12% faster                   17% faster
> dhclient            36% faster                    5% faster
> klogd                0%                           8% faster
> 

Adding some stats for arm-hf (bq 4.5)

Times are a cummulative user value for 5 consecutive runs of the parser
against a given profile.


			2.10+patch	no simple	no simple/2.10	2.9.1	no simple	no simple/2.9	2.10/2.9	2.10 no s/2.9 no s
chromium		34.07		35.75		104.93%		63.68	39.17		61.51%		86.98%		91.27%
cupsd			6.58		4.09		62.16%		11.97	4.22		35.25%		155.92%		96.92%
dhclient		4.98		3.3		66.27%		9.39	3.56		37.91%		139.89%		92.70%
dnsmasq			2.35		1.38		58.72%		3.74	1.47		39.30%		159.86%		93.88%
evince			79.85		239.55		300.00%		122.25	266.78		218.22%		29.93%		89.79%
firefox			33.64		35.02		104.10%		63.78	38.14		59.80%		88.20%		91.82%
klogd			0.78		0.53		67.95%		1.6	0.63		39.38%		123.81%		84.13%
Ubuntu-core-default	2.21		1.33		60.18%		4.99	1.49		29.86%		148.32%		89.26%
Ubuntu-personal-qml-app	11.08		6.3		56.86%		21.97	6.33		28.81%		175.04%		99.53%
Ubuntu-personal-webapp	17.8		11.8		66.29%		34.41	11.74		34.12%		151.62%		100.51%


So the case for arm-hf is different, for the simplification case the majority of cases regress but evince sees huge improvements. For the no simplification case we see slight performance improvements, and only one minor regression.